Rotary pump



oct. 2o,- 1959 c. G. GORDON 2,909,126

ROTARY PUMP Filed Nov. 7, 1955 Maj. Fly r-' 7 ke/Q01. l. G. @deva/v,

1N V EN TGR.

BY ath United States Patent ROTARY PUMP Carroll G. Gordon, Menlo Park, Calif.

Application November 7, 1955, Serial No. 545,174 4 claims. (cl. `10s-172) This invention relates to a new and improved rotary pump.

Hundreds or perhaps thousands of different rotary pumps have been designed in the past. In spite of the tremendous amount of work in designing these prior pumps, there still exists a demand for new and improved rotary pumps of virtually all different types. In particular, there is a demand for rotary pumps `which are specifically designed and adapted to be used for small hydraulic power units such as are employed with many servo-mechanisms. v

Many of the prior pumps have been of the centrifugal category. Those familiar with pumps will at once recognize the limitations of this type of equipment, and will realize that centrifugal pumps as such are not particularly adapted for use in pumping hydraulic fluids under high pressures.` Rotary vane or rotary gear pumps have frequently been used for this purpose. However, these conventional pumps also have a number of distinct disadvantages relating to their constructions which limit their adaptability.

In rotary vane pumps a number of different vanes are attached to a rotor so that as the rotor is turned within a cam ring the vanes flex, bend or otherwise move so as to vary the volume between the individual vanes, the rotor and the cam ring, causing a pumping action. With this type ofpump the actual pumping is performed outside of the rotor, and is controlled by the configuration of the cam ring and the movement of the vanes.

An object of this invention-is to provide a pump which in certain respects is similar to a rotary vane pump but which is different from a rotary vane pump in that the actual pumping' action is the result of piston movement being the result of rotation of a cam ring. With the preferred construction of the invention the pistons employed are mounted in a piston block in such a manner that they do not rotate and so that they project from the piston block so as to bear against a cam ring which is rotated during the operation of the pump itself.

In essence, the basic objective of the invention set forth in the preceding paragraph effectively summarizes a basic concept underlying this entire disclosure. A more detailed summary of the vactual subject matter involved-in this application is provided by the appended claims.

A further object of this invention is to teach the construction of effective, efficient, small, veasily constructed rotary pumps. Other objects of the invention as well as Y many specific advantages of it will be more fully apparent to Vthose skilled in the art to which the invention pertains from apconsideration of the remainder of this specification including the appended claims andthe drawings, in which: Fig. .1 is a side cross sectional View of a pump of this invention; Y i lFig. 2 is a cross sectional view taken at line 2-2 of Fig. 1;

Fig. 3 is an expanded isometric view showing the assembly of certain parts of the pump shown in Fig. v1;

- (Fig. 4 is an isometric view showing the assembly of other parts of this pump; and l tFigs. 5 and 6 are detailed views taken in the direction of line 5 5 of Fig. 1 illustrating the operation of the pump shown.

In all figures of the drawing, like numerals have been employed to designate like parts. It is to be understood that this invention is not limited to pumps having the precise constructional details indicated since a number of modifications can be made in the pump shown without departing from the essential nature of this invention.

lIn order to explain the invention, it is necessary to refer to the drawings. In Fig. 1 there is shown a pump 10, of the invention having a housing 12, within one end of which there is formed a first cylindrical section 14. This section is connected with a second cylindrical section section'1'4 is adapted toV be sealed by an end plate 218'.

This end plate may conveniently be secured -to the housing 12 by means of bolts 20 attached to a flange 22 formed on this housing. Within the end plate 118 there are formed inlet and outlet openings 24 and 26 leading to passages -28 and 30 which project from these openings through a piston block 32 formed integrally with the end plate v1'8 so as to project into the first cylindrical section 14. As is best seen in Fig. 3 of the drawings this piston block is provided with a flat surface 34 located perpendicular to the axes of the cylindrical sections 14 and 16. The exterior surface of the block 32 is of cylindrical configuration; and the entire block 32 is located so that the axis of this block is aligned with the axes of the cylindrical sections 1'4 and 16.

A short connecting passage 36 is located in the piston block 32 so as to project from the surface 34 to a cylinder 38 formed within the block 32. The passage 36 is preferably coaxially with the block 32; and the cylinder 38 is preferably formed so .that its axis intersects the axes of the block 32 and the cylindrical sections 114 and 16 at an angle of 90. As will be realized from a consideration of Figs. 2 and 3 of the drawings, the cylinder 38 extends completely through the block 32 so as to be open at each end. Y

Within the ends of the cylinder 38 there are located pisi tons 40, each of which is provided with a semi-cylindrical cup shaped depression 42 at the end generally remote from the piston block 32. Within each of these depressions 42 there are held small cylindrical rollers 44 in such a manner that coil spring 46 located within the cylinder 38 exerts pressure on the two pistons 40 tending to hold these rollers 44 against a cam ring 48 positioned around this block 32 within the first cylindrical sectionf14.

The exterior S0 of this cam ring 48 is in the shape of a cylinder while the interior of this cam ring is preferably in the shape of an ellipse so as to develop a pumping action as will be explained more fully later. During the operation of the pump 10, the cam ring 48 is turned through the rotation of a shaft 54. This shaft projects through the second cylindrical section 16 into the first cylindrical section 1'4 and is coaxial with these two sections. Upon the end of it within the first cylindrical section 1-4 there is formed a disc shaped plate 56 to which the cam ring 48 is secured by means of screws 58. 'Ihe configuration ofthe surface 60 of this disc shaped plate 56 is best seen from a consideration of Fig. 4 of the drawings. Within this surface there is formed a straight groove 62 which passes through the axis of the shaft 54, so as to connect the midpoints of two arcuate grooves 64 formed in thesurface 60.- These arcuate grooves are located with respect to thev axis of the shaft 54 a distance corresponding to the distance of the passages 28 and 30 to the axis of the piston block 32. Thus, with this construction, the grooves 64 match up with, or are aligned with, passages 28 and 30 during part of the rota-tion of the plateA 56. In essence, these grooves may be considered to act with the passages 28 and 30 as valves controlling the operation of the pump 10. If desired, they may be termed valve means.

The shaft 54 is supported within the housing y12. by a thrust spacer plate 66 located within the end of the first cylindrical section 14 adjacent to the second cylindrical section 16. This thrust spacer plate includes a cylindrical collar 68 bearing against the back of the plate 56 and a center opening 70 serving to support the shaft 54.

Within the end of 'the second cylindrical section 16 remote from the thrust spacer plate 66 there are positioned rings 72 and 74 forming a part of a conventional bearing race utilizing ball bearings 76. These rings are of conventional design and t against the walls of the second cylindrical section 16 and the exterior of the shaft S4 respectively; they are held against movement away from the housing 12 by means of a common snap ring 7S located in a groove 80.

Between the ring 72 and the thrust spacer plate 66 there is located a cylindrical outer shaft seal `82 having the form of a cylinder provided with a peripheral groove 84 formed therein. Within this groove 84 there is located a conventional elastomeric O-ring 86. Between the outer shaft seal 82 and the shaft 54 there are positioned an inner shaft seal 8S' and a center shaft seal 90. The center shaft seal 90 normally bears against the ring 74 and includes an external flange 92 fitting against the interior of the outer shaft seal 82. Between this ange and the shaft 54 there is located another O-ring 94. The ange 92 normally hits against the inner shaft seal 88. This inner shaft seal is formed as shown in Fig. l of the drawings so as to fit closely about the shaft 54 and so as to include two external flanges 96 and 98 between which there is positioned another O-ring 100. The flange 98 of the inner shaft seal 88 is normally held up against the flange 92 by means of a coil spring 102 which is positioned between this flange and the thrust spacer plate 66 as shown. Simultaneously the spring 102exerts a force on the plate 66 which transmits this force through the collar 68 against the back of the plate 56 so asv to hold this plate 56 against the surface 34.

The operation of the pump 10 is, in spite of the apparent complexity of the foregoing description, comparatively simple. When the shaft 54 is in a position so that the plate 56 is located as shown in Fig.v 5 of the drawings, the pistons 46 are located adjacent to one another within the cylinder 38. As the shaft 54 is rotated so as to move the plate 56 in a clockwise direction as viewed in Figs. 5 and 6 of the drawings, the cam ring 48 is moved so as to allow the pistons 40 to move away from one another towards the positions indicated in Fig. 6 of the drawings. As this occurs, the volume within the cylinder 38 between the two pistons 40 is increased and fluid is drawn through the inlet 24 and the passage 2S into one of the arcuate grooves 64 and thence, into the groove 62, the passage 36, and the cylinder 3S. As further' rotation occurs in the same direction, the cam ring is turned another 90 and the pistons 40 are forced back into the position indicated in Fig. 5 of the drawings, decreasing the volume between these pistons within the cylinder 38. This has the result of forcing the uid within this volume out through the passage 36, the groove 62 and one of the arcuate grooves 64 into the passage 30 and thence to the outlet 26.

In order that the valve arrangement may work satisfactorily, the grooves 64 are preferably formed of a length of 90 of a circle and the passages 28 and 30 intersect the surface 34 so as to be disposed at an angle of 90 of a circle with respect to one another. In order to provide lubrication for the rollers 44, passages 104 are provided within the pistons 40 so that part of the hy- 4 draulic fluid being pumped will flow in the depressions 42.

From the aforegoing description, those skilled in the art to which this invention pertains will realize that the pumping action achieved in this invention differs from that found in conventional pumps. They will further realize that the particular design of a pump shown relates to a very efficient, compact device capable of easily serving the purpose intended.

I claim:

l. A rotary pump which comprises: a housing; a piston block mounted in said housing; acylinder extending through said piston block; a shaft extending into said housing; a plate formed on said shaft within said housing; a ring mounted on said plate concentrically with the axis of said shaft, said ring including an internal cam surface positioned around said piston block; pistons fitting within said cylinder located in each end of said cylinder; a spring positioned within said cylinder, said spring normally urging said pistons toward said cam surface; an inlet into said housing extending through said piston block; an outlet from said housing extending through said piston block; a passage in said piston block leading from' the portion of said cylinder between said pistons to the outside-of said piston block; and valve means formed in said plate for selectively controlling iiuid flow from said inlet into said passage and said cylinder and from said j cylinder and said passage into said outlet said valve means fitting against said piston block; and means forcing said` valve plate against said piston block.

2. A rotary pump which comprises: a housing having an open end; an end plate mounted on said housing so as to close said open end in order to define a closed cavity within said housing; a piston block formed on said end plate so as to project into said cavity, said piston block having a flat end; a shaft projecting into said cavity at right angles to said hat end; a flat plate mounted on said shaft within said cavity, said at plate iitting closely against the flat end on said piston block; spring means `located around said shaft, said spring means serving to force said at plate against the flat end of said piston block; a ring mounted on said fiat plate concentrically with the axis of said shaft, said ring including an internal elliptical surface positioned around said piston block; means defining a cylinder within said piston block parallel to said ilat end, said cylinder being located so that its axis intersects the axis of said shaft at a right angle; pistons fitting within said cylinder located at each end of said cylinder; a spring positioned within said cylinder, said spring engaging said pistons so as to normally urge said pistons partially out of said cylinder against said elliptical surface; means defining a passage formed in said piston block leading from the center of said cylinder to said fiat end, said passage being aligned with the axis of said shaft; means defining a straight groove formed in the side of said flat plate adjacent to said flat end, said groove crossing the axis of said shaft; means defining two curved grooves formed in the side of said at plate adjacent to said flat end, each of said curvedgrooves having the shape of an arc of of a circle having its center coincident with the axis of said shaft, said curved grooves being symmetrically located about the periphery of said circle, and each of said curved grooves being intersected at its midpoint by said straight groove; means defining an inlet and an outlet in said end plate; and means defining inlet and outlet passages in said end plate and said piston block, said inlet and outlet passages extending frorn said inlet and said outlet to said at end of said piston block so as to be spaced from the axis of said shaft an amount equal to the distance of said curved grooves from the center of said shaft, said inlet and outlet passages being located 90 from one another around said shaft.

3. A rotary pump which comprises: a housing having an internal cavity formed therein; a piston block mounted Within said housing so as to project into said cavity, said block having a surface of rotation located within said cavity; a shaft extending into said cavity through said housing, said shaft having an end spaced from said surface of said block; a disc mounted on the end of said shaft within said cavity, said disc having a surface of rotation located against said surface of said block; spring means serving to force said surface of rotation on said disc against said surface of said block; a member mounted on said disc so as to extend around said block, said member including an internal eccentric surface spaced from said block; means defining a piston passage in said block, said passage being located generally within said internal surface; a piston located within an end of said passage, said piston fitting closely within said passage and being capable of movement within said passage; a spring located within said passage against said piston, said spring normally urging said piston away from said passage into engagement with said internal surface; means defining a iirst conduit extending through said block from said passage to said surface of said block; means defining inlet and outlet conduits leading into said housing through said block, said conduits terminating within said housing in openings located Within said surface of said block; and means defining grooves located on said surface of said disc so as to serve as valve means when said shaft is rotated, periodically placing said inlet and said outlet conduit in fluid communication with said first conduit.

4. A rotary pump which comprises: a housing having an internal cavity formed therein; a cylindrical piston block mounted within said housing so as to project into said cavity, said block having a flat end located within said cavity; a shaft extending into said cavity through said housing, said shaft having an end spaced from said end of said block, the axis of said shaft being aligned with the axis of said block; a disc mounted on the end of said shaft Within said cavity, said disc having a flat surface immediately adjacent to said end of said block; spring means forcing said flat surface of said disc against the end of said block; a ring mounted on said disc symmetrically about the axis of said shaft so as to extend around said block, vsaid ring including an internal eccentric surface spaced from said block, means defining a cylindrical passage extending through said block, said passage being parallel to said end of said block and crossing the axis of said block and located generally within said internal surface; a cylindrical piston located within each end of said passage, said pistons fitting closely Within said passage and being capable of movement within said passage; a spring located within said passage between said pistons, said spring normally urging said pistons away from said passage into engagement with said eccentric surface; means dening inlet and outlet conduits leading into said housing through said block, said conduits terminating within said housing in openings located in said end of said block an equal distance from the axis of said block along a line passing through the axis of said block; means defining two terminal grooves formed in said disc so as to extend in a circular path around-the axis of said shaft, said grooves being located at an equal distance from the axis of said shaft and being adapted to be moved in communication with said openings during rotation of said shaft; means defining a connecting groove formed in said disc so as to pass through the axis of said shaft adjacent said end of said block, said connecting groove connecting said curved grooves; and means defining a conduit extending along the axis of said block so as to place said passage in fluid communication with said connecting groove.

References Cited in the le of this patent UNITED STATES PATENTS 717,750 Johnston Jan. 6, 1903 784,569 Johnston Mar. 14, 1905 1,009,562 Pedersen Mar. 21, 1911 1,526,343 Jouanneaux Feb. 17, 1925 2,227,740 Friedell Jan. 7, 1941 2,599,609 Carey June 10, 1952 2,651,999 Harrington Sept. 15, 1953 2,660,992 Roosa Dec. 1, 1953 2,712,794 Humphreys July 12, 1955 

